Field of the Invention
One or more embodiments of the present invention relate to a display device, and more particularly, to a liquid crystal display device.
Description of the Related Art
Display devices are necessary for computer monitors, televisions, cellular phones, portable terminals, etc. Examples of the currently most widely used flat display devices include liquid crystal display devices and organic light-emitting display devices.
Liquid crystal display devices which are one of the currently most widely used flat panel display devices include two flat plates on which pixel and common electrodes are formed, and a liquid crystal layer disposed between the two flat plates. When voltages are applied to the pixel and common electrodes to form an electric field across the liquid crystal layer, the arrangement of liquid crystal molecules of the liquid crystal layer is varied by the electric field, and thus the polarization of light passing through the liquid crystal layer is controlled to display images.
Vertically aligned mode liquid crystal display devices in which major axes of liquid crystal molecules are perpendicular to a display plate when an electric field is not applied thereto have been developed.
A major concern about vertically aligned mode liquid crystal display devices is to guarantee a wide angle of view, and thus cut portions such as fine slits are formed in electrodes for driving pixels. Since the cut portions determine the tilt direction of liquid crystal molecules, the tilt direction of the liquid crystal molecules may be distributed in many directions by properly arranging the cut portions, so as to widen an angle of view. In the case of a liquid crystal display device in which fine slits are formed in an electrode to form a plurality of fine branch electrodes on the electrode and side visibility is guaranteed by applying different voltages to two sub-pixels formed by dividing each pixel, since a switch driving unit occupies a relatively large area in each pixel, the aperture ratio of the liquid crystal display device is low, and thus the transmittance of the liquid crystal display device is low.
In development of high-resolution panels using liquid crystal display devices, the transmittance of the liquid crystal display devices may be a major factor, and thus it may be difficult to use the above-described method of dividing each pixel into two sub-pixels.
In addition, the speed of response of liquid crystal is a major factor when the driving frequency of a liquid crystal display device is increased and the liquid crystal display device is applied to a three-dimensional product. A decrease of a cell gap may be an important factor for improving the speed of response of liquid crystal. However, if a cell gap is simply reduced in an existing structure, a liquid crystal having a high refractive index may have to be used.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.